The Early Detection Program (EDP) in Dade County, Florida provides a unique opportunity to evaluate an on-going, community-based, comprehensive breast cancer detection program. The applicant proposes to determine factors which either contribute to or inhibit the effectiveness of such an innovative community-based program. Factors affecting its generalizability will be examined with an explicit, concomitant goal to transfer the evaluated screening technology to other communities. Factors to be examined include utilization variables and continuity of care issues (including time elapsed) and patient satisfaction. Impact of the EDP will be measured relative to screening and biopsy rates, cancers detected, shifts in staging, survival and mortality. It is estimated that data on over 45,000 screening and more than 300 cancers, as well as comparable controls, will be available by the end of the proposed evaluation. Specifically, the study will compare random samples of screenees (selected from the DETECT data base) and non- screenees (selected from Primary Health Care Center (PHCC) intake/medical records. Additionally, a case (mammography users)/control (mammography non-users) study will be performed utilizing records from PHCCs and from the University of Miami, Jackson Memorial Medical Center (UM/JMMC). An additional unique feature of this study is the opportunity to do two case control analyses by comparing EDP cases to UM/JMMC controls: 1) a comparison of stage distribution and, 2) a cost-benefits analysis utilizing cost and charge data.